EP 2095328 B1 20160831 - CALIBRATION OF VOLUME ACQUIRED IMAGES
Title (en)
CALIBRATION OF VOLUME ACQUIRED IMAGES
Title (de)
KALIBRATION VON VOLUMENBESCHAFFTEN BILDERN
Title (fr)
ÉTALONNAGE D'IMAGES DE VOLUME ACQUISES
Publication
Application
Priority
EP 2006011829 W 20061208
Abstract (en)
[origin: WO2008067838A1] A method is disclosed whereby a prior reference image is used as a calibration source for a volume image prepared using less accurate apparatus, such as during therapy. Thus, a volume image of a patient is prepared by acquiring a reference image of the patient suitable for treatment planning purposes, acquiring a subsequent image of the patient, selecting a plurality of voxels in one of the subsequent image and the reference image, and preparing a histogram of the voxel values in a region around each selected voxel, to form a first set of histograms, identifying the corresponding regions in the other image and preparing a histogram of the voxel values in each of those corresponding regions, to form a second set of histograms, for each histogram in the first set, identifying a transformation that transforms it to be substantially the same as the corresponding histogram of the second set, thereby to derive a set of transformations, and applying a transformation to voxels in the subsequent image based on the set of transformations. In this way, an image can be obtained from a cone beam CT apparatus and corrected using the voxel intensities from a recent reference image as a norm. Provided that the reference image is relatively recent, there should not be sufficient gross changes in the volume image to affect this process. Changes between the reference and subsequent images such as the movement of internal structures will be preserved since the method compares local histograms and this corrects intensities, not shapes. Likewise, the use of histograms around a local region of the volume image will mean that gently varying artefacts such as the cup artefact will be substantially eliminated. The volume image thus derived can then be used for treatment planning, such as in radiotherapy.
IPC 8 full level
G06T 5/00 (2006.01); G06T 5/20 (2006.01); G06T 5/40 (2006.01)
CPC (source: EP US)
G06T 5/20 (2013.01 - EP US); G06T 5/40 (2013.01 - EP US); G06T 5/94 (2024.01 - EP US); G06T 2207/10081 (2013.01 - EP US); G06T 2207/20012 (2013.01 - EP US)
Citation (examination)
EP 0905650 A2 19990331 - CANON KK [JP]
Designated contracting state (EPC)
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR
DOCDB simple family (publication)
WO 2008067838 A1 20080612; EP 2095328 A1 20090902; EP 2095328 B1 20160831; US 2010322491 A1 20101223; US 8224055 B2 20120717
DOCDB simple family (application)
EP 2006011829 W 20061208; EP 06829430 A 20061208; US 51783909 A 20090605